Gas-Lift Surveillance Techniques

Jim Hall, Shell International EPCleon Dunham, Oilfield Automation

20 – 30 Participants

Gas-Lift Surveillance Techniques• Objectives

• Deep• Stable• Optimum

• Data gathering / reporting• Charge – 95% of data not used• Objective

- Collect key data once per minute- Have “system” check all data- If well is OK, nothing is reported- If well is sick (exception), it “calls for help”- People use data to troubleshoot problem wells

• What data is needed?

Gas-Lift Surveillance• Measurements Need Want Use

Surface• Pinj Y Y GL analysis• Qinj Y Y GL

analysis/control• Pwh Y Y GL analysis• Qliq Y GL

optimization• Twh Y Detect change

in H2O• Pfl Y GL analysis• Tambient Y Twh analysis

Downhole• Pwf Y GL

optimization• T Y GL analysis• Qinj Y GL

analysis/control• Qsinglephase Y GL

optimization• Tcontinuous Y GL

troubleshooting

Gas-Lift Surveillance• Performance Indicators

• TGLR Hydraulic effectiveness

• IGLR Economic effectiveness

• FGLR Must be calculated• BS&W What is being lifted• Others

• What if Downhole Instruments Fail• Run flowing gradient survey• Conduct accurate well test• Calibrate multi-phase model

• Use calibrated model with measured surface data in between surveys and well tests

Gas-Lift Control MethodControl Method Frequency of Use

• Lift gas rate• Manual Common• Automatic Fairly common• Downhole1 Very new

• Injection pressure• Manual -• Automatic Rarely• Downhole1 Very new

• Production pressure• Manual Fairly common• Automatic Very

specialized

1 If using downhole control, need automatic fallback to surface method